It has been postulated that ethical decision making regarding medical interventions for the terminally ill would be improved by widespread use of comprehensive living wills. Use of the Do Not Resuscitate order, although helpful, has been shown to be inadequately used, and is only one of a large spectrum of decisions that need to be made. It has therefore been suggested that the best available protection of patients' rights to choose limited or extensive medical intervention would be provision for making a comprehensive living will for all patients, analogous to the routine preparation of regular wills. We will study features of this suggestion, including the practicability of physicians opening the discussion in primary care and specialty care practices for ambulatory patients. The study will make use of a specifically designed living will format with options for a variety of medical interventions in case of several types of impairment. This living will is included as part of a survey designed to assess inclination to discuss terminal care and to give preferences for treatment in specific circumstances, and preferences for who should make which decisions. The durability of patients positions will be assessed by re-administering the survey 6 to 12 months after the initial survey and at the time of any interium hospitalization. Cohorts include the following: a) 388 patients seen in primary care physicians practices. b) 291 patients with acquired immunodeficiency syndrome. These patients in these two cohorts will be surveyed either by the physician or a research assistant. c) 410 patients from a telephone registry. These individuals will be surveyed by telephone. The study is expected to assess whether comprehensive living wills are practical for physicians and patients, and whether they are desired by patients. The study is expected to provide some models for how physicians and patients can handle the process of indicating preferences for care in case of catastrophic illness, and a model living will format.